# Weighted average - math problems

#### Number of problems found: 44

• Athletic competition In a 400 meter athletic competition, a participant covers the distance as given below. find the average speed? first 80 meters 10 m/s next 240 meters 7.5 m/s last 80 meters 10 m/s
• Carpenters Carpenters 1 and 2 spend ten days and five days respectively to make one table. If 50 tables were made by the first carpenter and 30 tables were made by the second carpenter, What is the average time spent on the products?
• Final exam There are 5 learners in a class that has written a final exam Aleta scored 55% vera scored 36% and Sibusiso scored 88% if Thoko scored 71% and the class average was 63%. What was Davids score as a percentage?
• Standard deviation Find standard deviation for dataset (grouped data): Age (years) No. Of Persons 0-10 15 10-20 15 20-30 23 30-40 22 40-50 25 50-60 10 60-70 5 70-80 10
• Peroxide How many ml should we pour 30% of peroxide (H2O2) into 100ml H2O to give a 20% solution?
• Octane value I loaded 10L 95 octane gasoline and 5L 100 octane gasoline. What is the resulting octane value of the gasoline in the tank?
• CuSO4 mixture How many grams of solid CuSO4 we have to add to 450g of 15% CuSO4 solution to produce a 25% solution?
• 5 people Five people have \$122000 each, and one person has \$539000. How much should each person (equally) pay?
• Mixture 2 How many liters of water must be added to 7 liters of a 20% solution to obtain a 10% solution?
• Dried fruit The manufacturer produces a mixture of dried fruit. He purchased: 10kg pineapple for 200 Kc/kg 2kg papaya for 180 kc/kg 1kg of banana for 400 Kc/kg How many kgs of raisin for 80 Kc/kg must be put into the mix by the manufacturer so that the production pri
• Candies There are two types of candies in the store at 20 CZK/kg and 80 CZK/kg. How much will be cost a mix if we mix 22kg cheaper and 4kg more expensive candies?
• Pharmacy The pharmacy adds to 3 liters of 95-percent alcohol 5 liters of 38.04 percent alcohol. How much percent alcohol the pharmacy got?
• Kerosine and petrol If 4 liters of petrol containing 15% kerosine are added to another 7 liters of petrol containing 10% kerosine, what percentage of the petrol is kerosine?
• Hydrochloric acid Determine the concentration of which must have a solution of hydrochloric acid that mixing 10 l of the solution with 8 liters of 26% solution to get the solution with a concentration of 50%?
• Contestants In the competition it was possible to get 0-5 points. In fact, 5 contestants of the 15 best contestants has earned 5 points or 4 points (which have won 10 contestants). The number of contestants who earned 3 points was the same as the number of contestant
• Float boya A 0.5 meter spherical float is used as a location mark for a fishing boat anchor. It floats in salt water. Find the depth to which the float sinks if the material of which the float is made weighs 8 kilograms per cubic meter and salt water weighs 1027 kg/
• Inscribed circle Write the equation of a incircle of the triangle KLM if K [2,1], L [6,4], M [6,1].
• Vinegar What percentage vinegar we get if we mix 1 if dm³ eight percent vinegar with 1.5 dm³ six percent vinegar?
• Alcohol 2 Two types of alcohol one 63% and second 75% give 20 liters of 69% alcohol. How many liters of each type are in the mixture?
• Center of gravity The mass points are distributed in space as follows - specify by coordinates and weight. Find the center of gravity of the mass points system: A1 [1; -20; 3] m1 = 46 kg A2 [-20; 2; 9] m2 = 81 kg A3 [9

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